HELP! 5 Dead Fish

Dez92

Hey everyone,

This has been a sad morning...I went to feed my fish and noticed I had FIVE dead fish (4 Neon Tetra and a mystery fish) in my aquarium of otherwise seemingly healthy fish... :/ I'm wondering if anyone has any idea what might be going on or if I need to worry about my other fish... I do have Paraguard and Ich-X on hand.

A couple of the danio have odd gills, red/flared that have been like that for a long time, I think since they've been big enough to see properly (I was inexperienced and didn't cull). They don't behave oddly or seem to be suffering.

A bit about my aquarium, it's a heavily planted 32.5 gallon Fluval Flex with no mods (filter and light that came with it) running since March 2020. It's got a heater and water kept at 76F. I have a pic attached, but there are a few more plants added since this pic was taken.

I've got 8 Danio that I raised from fry and have been in the tank since its been cycled, 3 Neon Tetras since Jan 2021 (I had 7, found 4 dead this morning), 3 Pearl Gourami added April 5 2021, 6 Endler added May 9 2021, 3 Oto with plump bellies since May 22, 2021 (I had 4, can only see 3 and wondering if the mystery fish was the 4th oto. Pic of dead fish attached), an accidental SAE since May 22 2021 (was in the bag with my oto from my lfs and has the markings and shape of SAE. Highly doubtful it's a false SAE, blurry pic attached for reference; suckers are fast), 3 Amano shrimp since Jan 2021, and 1 Bamboo shrimp since April 5, 2021.

Nitrate: less than 5, Nitrites: 0, Ammonia: 0, pH: 7.0. I do water changes every 1-2 weeks of 30-50% and treat with Nutrafin Aqua Plus. I have fluval stratum for substrate and don't usually vacuum the substrate unless there's a large build up, there usually isn't. I also dose with Thrive S on water changes and once or twice in between. I was using Flourish Excel because I do get quite a bit of hair already but haven't used it in several months since I learned it can be harmful to invertebrates.

I feed my fish every day with Bug Bites, unless I feed frozen blood worms which is once a week. I like to give them a fasting day once a week if they're looking pudgy. I grind Bug Bites and Fluval shrimp pellets for the Bamboo shrimp.

Sorry for the long post...I went off the emergency template.
Thanks.
 

Frank the Fish guy

When I have fish that appeared healthy the day before, but find them dead in the morning - especially a group of fish, the first thing I suspect is low oxygen overnight, especially in a highly planted tank without much aeration or surface agitation. Oxygen can dip to dangerously low (for fish) levels sometimes at night in a highly planted, low water movement tank.

Getting to grips with your C02 and 02 concentrations in the water is a good next step for you to consider if you want to understand what is going on.

Or you can just add more surface agitation and try to find a balance that makes fish and plants both happy.
 
Upvote 0

Dez92

When I have fish that appeared healthy the day before, but find them dead in the morning - especially a group of fish, the first thing I suspect is low oxygen overnight, especially in a highly planted tank without much aeration or surface agitation. Oxygen can dip to dangerously low (for fish) levels sometimes at night in a highly planted, low water movement tank.

Getting to grips with your C02 and 02 concentrations in the water is a good next step for you to consider if you want to understand what is going on.

Or you can just add more surface agitation and try to find a balance that makes fish and plants both happy.
Thanks! I didn't think of this. I have adjusted the flow so there is more surface agitation for the time being. I'm not sure how to check for the concentration of O2/CO2, I assume there's kit lol, I'm going to do a bit of research into this. I don't have any CO2 set up in my tank. It is something I've been looking into.
 
Upvote 0

Frank the Fish guy

Often all it takes is changing the angle that the filter puts water back into the aquarium so that the surface gets rippled. Plants can actually use up oxygen when the lights are out. So the surface agitation keeps the dissolved gasses in equilibrium with the atmosphere and keeps the 02 levels from dipping low at night. It is also good to have good circulation in the tank so there are no dead spots. Pull water in from low and return high for example.

If you stick your hand in and find the water to be different temps at different places then there is not good circulation.

Plants can be happy with periods of low 02, they can just wait for it later. But fish can't survive a brief period with low 02.
 
Upvote 0

Dechi

It’s also possible your fish died because neons have a high mortality rate for no specific reason other than being fragile.

And otos are also known to be hard to keep. The dead fish on the picture sure looks like an otocinclus. And your SAE is the real thing if the black line goes all the way to the back of the tail and he doesn’t have a sucker mouth.
 
Upvote 0

Similar Aquarium Threads

Replies
6
Views
104
SarahPar
Replies
2
Views
106
Isitwindyyet
Replies
7
Views
227
Cherryshrimp420
Replies
6
Views
164
bcsay720
Replies
14
Views
597
ANudibranch

Latest Aquarium Threads

Top Bottom